Draft: Ci test hanging timescan issue 3877

Reproduce #3877 (closed) on bcu-ci-lab1

while pytest tests/nexus_writer/test_nxw_timescan.py::test_nxw_timescan -s --log-cli-level=debug > test.log 2>&1;do echo "ok";done

Look in the logs for

• Stop scan (timeout=100) ...: this is the point whether the test times out
• Events per channel:: this is the point where the test checks for new channels events
• Chain tasks: these or the logs of the chain events